The present invention relates to an image forming apparatus. More specifically, the present invention relates to an image forming apparatus capable of drawing a fine line through a correction process.
In a conventional image forming apparatus, a fine line is drawn based on a width or a length of one pixel according to a set output resolution. With recent technological advancement, a resolution of an image forming apparatus has increased from about 300 to 600 dpi (dot per inch) to 1200 to 2400 dpi, thereby making it possible to obtain a resolution with higher precision. Further, Patent Reference has disclosed a technology for forming an image suitable for a fine line through controlling a pulse number.
Patent Reference: Japanese Patent Publication No. 08-118703
In the conventional image forming apparatus, when the resolution increases, it is difficult to draw a line having one pixel length. Even when such a line is drawn, it is difficult to visually recognize the line. For example, when a fine line is drawn at the resolution of 600 dpi, one pixel has a size of about 0.04 mm. In this case, it is possible to visually recognize the fine line. When a fine line is drawn at the resolution of 1200 dpi, one pixel has a size a half of that of 600 dpi. When a fine line is drawn at the resolution of 2400 dpi, one pixel has a size a quarter of that of 600 dpi. Accordingly, depending on an apparatus, it is difficult to arrange dots due to a small width of a line. Even when such a line is drawn, it is difficult to visually recognize the line.
FIGS. 2(a) to 2(d) are schematic views showing lines drawn with a conventional image forming apparatus. FIG. 2(a) is a schematic view showing a line having one pixel length drawn according to a dashed line drawing command. FIG. 2(b) is a schematic enlarged view showing a line having one pixel length drawn at a resolution of 600 dpi. FIG. 2(c) is a schematic enlarged view showing a line having one pixel length drawn at a resolution of 1200 dpi. FIG. 2(d) is a schematic enlarged view showing a line having one pixel length drawn at a resolution of 2400 dpi.
As shown in FIG. 2(a), a dashed line including the lines having one pixel length is drawn. When the dashed line is drawn at the resolution of 600 dpi, the line having one pixel length shown in FIG. 2(b) is printed.
When the dashed line is drawn at the resolution of 1200 dpi, the line having one pixel length shown in FIG. 2(c) is printed. In this case, the line having one pixel length has a width a half of that of 600 dpi. When the dashed line is drawn at the resolution of 2400 dpi, the line having one pixel length shown in FIG. 2(d) is printed. In this case, the line having one pixel length has a width a half of that of 1200 dpi, or a quarter of that of 600 dpi.
Accordingly, when the resolution increases, it is difficult to draw the line having one pixel length. Even when such a line is drawn, it is difficult to visually recognize the line.
In the view of the problems described above, an object of the present invention is to provide an image forming apparatus capable of solving the problems of the conventional image forming apparatus. In the image forming apparatus, a length of a specific portion of a dashed line is determined. When the length of the specific portion is smaller than a specific length, a correction process is performed, so that the length of the specific portion is extended up to the specific length. Accordingly, when a dashed line including a line portion having one pixel length, it is possible to print and make the line portion having one pixel length visually recognizable.
Further objects and advantages of the invention will be apparent from the following description of the invention.